This invention relates to process equipment using reactive gases and, in particular, to plasma reactors using various gases.
In the past, the delivery of gases to a plasma reactor comprised a series of relatively permanent connections through various piping, valves, and blocks. Changes or adjustments are typically difficult due to the permanence of the connections as well as their physical location in the equipment. This often results in gas handling portions being difficult to adjust or repair after the equipment is installed.
Plasma reactors use a variety of gases to effect etch or deposition of material on a semiconductor wafer. Some of the gases used may be toxic, corrosive, or both. Thus, care must be exercised when adjusting or repairing the reactor. In addition, disassembling the plumbing connections can introduce leaks, moisture and other contaminants which negatively effect the operation and life expectancy of the gas system.
The nature of the gases produce another difficulty, viz. the need to purge the system after each system shutdown or period of disuse. Particularly troublesome is the contamination of the reactor chamber. Aside from the volume of the chamber, the internal shape typically presents pockets in which a contaminating gas, eg. atmosphere, can reside despite repeated purging. It is thus highly desirable for one to isolate portions of the gas handling system so that the entire system need not be purged and/or exposed to air.
The manufacture of semiconductor devices using a plasma is characterized by a continued striving for and improvement in the control of the process. One item which has greatly assisted in this endeavor is what is known as a mass flow controller. In these devices, the mass of the gas flowing to the reactor chamber is metered rather than the volume. A typical reactor may have several of these devices located throughout the apparatus. Unfortunately, mass flow controllers are not noted for reliability. Thus, there are frequent periods when the apparatus is inoperative during adjustment or replacement of the mass flow controller.
Even when running properly, small leaks in the gas system may cause problems if the gas is corrosive. Electrical connectors and wiring can deteriorate rapidly in a corrosive atmosphere. One approach to cure this problem is to securely isolate the electronics from the gas, eg. with appropriate sleeves, boots, potting compound or the like. This makes it very difficult to repair or adjust the electronics in the system.
In view of the foregoing, it is therefore an object of the present invention to improve gas control reliability in wafer processing equipment.
Another object of the present invention is to provide means for isolating gas lines in plasma reactor apparatus.
A further object of the present invention is to provide means for enabling equipment using reactive gases to be modularly constructed.
Another object of the present invention is to provide plasma reactor apparatus having a local atmosphere.